Innovation provider

Thermodyna GmbH 


Volker Bergholter
Wilhelm–Bock-Weg 11
DE-22 297 Hamburg
Tel.: +49 (0)40 511 07 00
Fax.: +49 (0)40 511 46 01


The main component of the Schukey machine consists of two interlocking rotor blade crosses which can move against each other and rotate in the same housing. Each cross is driven in such a way that they do not turn uniformly at the same speed, but out of phase with each other at alternately faster and slower speeds. As a result, the eight housing chambers formed by the rotor blade crosses become bigger and smaller eight times per revolution, i.e. their contents are compressed and expanded accordingly.
The ST can be operated with compressed air, hot air, hot gas and steam as an expansion engine to convert heat into mechanical energy in the low temperature and pressure range. The demands on a technology to operate under these conditions are high. It has to
  • have a very high flow rate to be able to offset the lack of specific energy of a medium,
  • be small and compact in order to be used also in areas of limited space,
  • feature extremely low internal fraction and
  • it has to be inexpensive and rugged to run profitably also with lower efficiency due to physical reasons.
At present, there is no technology apart from ST which meets these requirements.


  • the engine consists of less than 50 parts of which only 16 are moving, resulting in low abrasion and consequently in low maintenance and operating costs.
  • compact design allows for retrofitting of existing CHP plants
  • good part-load performance, particularly, if there is no continuous heat flow
  • low rotational speed: no need for a geared transmission between engine and generator

Innovative aspects (ecologic, social and economic)

Schukey is the technique of choice to improve the electricity yield of CHP plants. In general it is suitable to generate electricity from low temperature heat sources like waste or solar heat. In combination with cooling (trigeneration), ST provides the opportunity of electricity production or air conditioning on demand. In addition, 77% of the heat demand of an average private house is covered on a renewable basis. Thus, the technology has the capacity to cut CO2-Emissions from private homes significantly. No HFC refrigerants with a high greenhouse potential are needed for cooling compared to standard split air conditioning systems. 

Application examples

Co-generation; trigeneration; air conditioning; solar energy 


Schukey clearly increases the electrical efficiency of CHP plants and therefore increases profitability.
Costs of refrigeration are about €0.05 per kWh cooling output compared to €0.14 with standard techniques. This means that ST is also an economic alternative to multi-split or VRF systems in commercial air conditioning. 

Current stage of development

Development phase – laboratory tested

Intellectual Property Rights

Patent granted
Patent-Nr. EP 0 945 592 A1 

Country of origin


Country of application



National Contact Point

Daniel de Graaf
Wörlitzer Platz 1
06844 Dessau-Roßlau

Tel. +49 (0)340 21033407
Fax. +49 (0)340 21043407